1992 Ford F150 - primer - Photo 13

11. Here you can see the Keystone Automotive PPG K36 primer surfacer being applied over the PPG DPX 170 self-etching primer. Self-etching primer isn't always used by body shops, but we felt it was mandatory due to the harsh conditions our truck would endure. The self-etching primer bonds with the metal and is said to stop corrosion caused by rock chips and things of that nature.